Automatic box spring corner cutter



United States Patent Alfred J. Withoff Wayzata, Minnesota [72] inventor Chaska, Minnesota a corporation of Minnesota [54} AUTOMATIC BOX SPRING CORNER CUTTER 11 Claims, 11 Drawing Figs.

144. l34, 136.7, l-il.2

[56] References Cited UNITED STATES PATENTS 3,333,614 8/1967 Furtado etal,

Primary Examiner-Gil Weidenfeld Attorney- Me Dougall, Hersh, Scott and Ladd ABSTRACT: A construction for providing curvilinear corners on box spring frames comprising a movable supporting bed for the frames. A plurality of corner cutters are initially positioned in spaced relationship relative to the frame. and the supporting bed is adapted to then move the frame into position adjacent the cutters. The corner cutters are shifted into cutting position and are then operated to remove material for providing the curvilinear corner surfaces. The corner cutters include frame engaging means so that upon movement of the corner cutters into cutting position, the frame will be located in position, and so that frames of somewhat irregular dimensions can be readily handled.

Patented Oct. 13, 1970 l of 4 Sheet INVEN T012 fllfrecl J Wz'ilzqf Patented Oct. 13, 1970 Sheet' of4 FIGQ 4 AUTOMATIC BOX SPRING CORNER CUTTER SPECIFICATION This invention relates to a construction for cutting the corners of frames used in the manufacture of box springs. The frames usually consist of a plurality of longitudinally and horizontally disposed wooden pieces secured together to form a rectangular construction.

In the manufacture of frames for box springs, it is often difficult to provide consistent dimensions. This has led to difficulty in the cutting of corners on the frames since jigs or other devices for holding the frame during cutting did not accommodate dimensional variations. This is particularly true where the dimensional variations result in the frames being out of square. In addition, box spring sizes are not uniform throughout the country so that manufacturers have been required to provide different corner cutting setups for frames of different sizes.

It is a general object of this invention to provide an improved apparatus for the handling of box spring frames so that cutting of corners on the frames can be efficiently accomplished.

It is a more specific object of this invention to provide a construction for cutting corners on box springs wherein frames which vary from desired dimensions can be easily accommodated, and which can be easily adjusted to provide for the cutting of frames of different standard sizes.

These and other objects of this invention will appear hereinafter and for purposes of illustration, but not of limitation, specific embodiments of the invention are shown in the accompanying drawings in which: 7

FIG. I is a schematic side elevational view of the construction of this invention;

FIG. 2 is a plan view of the construction shown in FIG. 1;

FIG. 3 is a top plan view of a router assembly employed during the corner cutting operation;

FIG. 4 is a bottom plan view of the assembly shown in'FlG.

FIG. 5 is an enlarged fragmentary view taken about the line 5-5 of FIG. 3-,

FIG. 6 is a fragmentary view, partly in section, illustrating the lifting mechanism employed for the frames;

FIG. 7 is a detail plan view illustrating microswitch and end gate means employed in the construction, the gate being in the closed position;

FIG. 8 is a detailplan view of the construction shown in FIG. 7 in the open position;

FIG. 9 is an enlarged sectional view taken about the line 9-9 of FIG. 7;

FIG. 10 is a detail plan view of entrance gate means illustrated in the closed position; and

FIG. 11 is a detail plan view of entrance gate means illustrated in the open position.

The construction of this invention generally consists of a supporting bed for receiving frames. The bed includes means for lifting the frames into position adjacent comer cutters, and the corner cutters are, therefore, automatically located in a starting position. The corner cutters are operated for removing material to provide curvilinear corner surfaces, and the frame is then discharged from the cutting position to permit movement of the next frame into the cutting position.

Three corner cutters are preferably mounted on movable supports, and one of the corner cutters is held stationary. Upon location of the frame adjacent the corner cutters, the cutters are shifted into engagement with the frame. This serves to lock the frame in position during the cutting operation, and it also provides a means for accommodating frames which are dimensionally inaccurate. Thus, the corner cutters will shift until engaged with the frame, and will thus move to a starting position irrespective of the tolerance variations in the particular frame being cut.

FIGS. 1 and 2 illustrate frames 10 of the type normally utilized in conjunction with box springs. The frames include a lon- 14 are secured together by side frame members 16 and I8. The front and rear extremities of each frame are formed by rectangular, transversely disposed boards 20. These boards 20 normally present square corners, and these are the corners which are to be rounded off as illustrated at 22.

The frames 10 are placed on a conveyor bed made up of rollers 24 priorto the cutting operation. The rollers operate to move the frames from the loading station 26 to the cutting station 28, and then to the discharge area 30. The rollers 24 are preferably continuously driven so that the frames will be moved automatically unless impeded by gates.

FIG. 2 illustrates a first pair of gates 32 which serve to block the entrance to the cutting station 28. The gates 32 comprise blocking fingers operated by pistons 34, the extending stroke of the pistons causing the fingers to pivot about the axis 36 and thereby clear the path for a frame 10. When the frame I0 moves into the cutting station, it is blocked by end gates 38 operated by pistons 40.

Routers 42 are positioned above the rollers 24 and each frame 10 is adapted to be lifted into position adjacent these routers. The mechanism for lifting the frames comprises a pair of transversely extending rails 44 normally positioned just beneath the plane defined by the upper peripheral portions of the rollers 24.

The rails 44 are connected to rods 46 and links 48 are attached at the lower ends of the rods 46. Lever arms 50 and 52 are attached at the opposite ends of the link 48, and the pivotal movement of these lever arms is controlled respectively by the connecting rods 54 and 56. The lever arm 58 which is pivotally attached to the frame of the construction 60 is controlled by piston 62. When the piston rod 64 is extended, pivotal movment of the arm 58 will result in pivoting of the lever arms 50 and 52 whereby the links 48 will raise the rods and associated rails to thereby lift the frame 10 carried by the rails. When the frame is in the upper position, the routers 42 are operated for cutting the corners of the frame.

FIGS. 3, 4 and 5 illustrate the construction of the routers 42. This construction includes a supporting plate 66 which may be bolted onto the stationary frame of the construction. It will be appreciated that any type of supporting frame, for example formed of lengths of angle iron, may be utilized for supporting the plates 66.

A pair of bars 68 are bolted onto the plate 66 in spaced relationship with the upper surface of the plate. The bars 68 thus provide a clearance for receiving the side edges of movable plate 70. The position of the plate 70 relative to the plate 66 is controlled by the piston 72. When the piston rod 74 is pulled in, the plate 70 will be in the forward position shown while extension of the piston rod will shift the plate rearwardly. The limit of rearward movement is controlled by means of a centering stop 76 attached along the back edge of the plate 70. This centering stop cooperates with centering block 78 fixed on the stationary plate 76.

A second piston 80 is mounted on the plate 70 for movement therewith. Specifically, a bracket 82 carries an outwardly extending tab 84 for attachment of the end 86 of the piston.

The end 88 of piston rod 90 is pivotally secured to the hinge plate 92. This hinge plate is integrally formed with a link 94, and one end of the link is pivotally connected at 96 to the stationary bar 98 extending across the plate 70. The other end of the link is pivotally attached at 100 to a lip 102 extending outwardly from the supporting base 104 provided for the motor I06. A second link 108 interconnects a second lip 110 with the bar 98.

The motor 106 of each of the routers carries a downwardly extending router bit 112. A curvilinear slot 114 is defined by the plate 70 to provide a path for movement of the bit during the cutting operation. It will also be noted that the supporting plate 66 defines an enlarged opening 116 to permit shifting movement of the plate 70 while keeping the bit free to perform the cutting operation.

The underside of the plate 70 defines a pair of stops 118 disposed at 90 relative to each other. When the piston 72 is in the retracted position illustrated, the stops I18 engage the side edges of the box spring frame 10. Thus, these side edges serve as the means for limiting movement of the plate 70. The router will, therefore, always be in the same position relative to the frame prior to the cutting operation.

It will be noted that a clearance shown at 120 is provided between the outer edges of the plate 70, and the inner surface of the slot defined by the bars 68. In addition, the piston rod 74 is pivotally connected at 122 to the plate 70. Accordingly, if the corner of the frame engaged by the stops 118 is out of square, the plate 70 will shift to accommodate this variation so that the router bit will still be properly positioned prior to cutting, and so that the curvilinear surfaces provided will be as uniform as possible.

In the preferred form of this invention, three of the router constructions are of the type shown in FIGS. 3, 4 and 5. The fourth router may be identical; however. the plate 70 will be fixed relative to the plate 66, there being no need for the piston 72. When the frame 10 is raised into position adjacent this stationary router, the frame edges will be in spaced relationship relative to the surfaces of the stops 118. Shifting movement of the other plates will operate to force the frame into engagement with these stationary stops. The plate which is diagonally opposite the stationary plate can be moved first to thereby lock the frame in position prior to movement of the other two plates.

FIGS. 7 and 8 illustrate a preferred form of gate means 38 suitable for use at the exit end of the cutting station 28. In this arrangement, the piston 40 is mounted on a bracket 130 secured to the stationary frame of the construction. The piston rod 132 is connected to link 134. The other end of the link 134 is fixed to the pin 136 by means of set screw 137. The lower end of the pin 136 is tied to the stopgate 138 for microswitch 140. A flexible blade 142 is secured to an upstanding pin 144 mounted on the bracket 138. The stopgate 138 serves as a stop means and also as an actuating means for the microswitch.

FIGS. 9 through 11 illustrate a suitable gate means 32 for the entrance end of the cutting station 28. In this embodiment, the piston rod 146 is pivotally attached to a link 148 which is tied to a pin 150 by means of set screw 152. The gate member 154 shifts from a blocking to a nonblocking position in response to operation of the piston.

FIG. 6 illustrates some of the details of the construction particularly the lift bars 44 and the conveyor means. It will be noted that the rod 46 which carries the bars 44 are received by sleeves 160, the sleeves being secured to transverse supports 162. The bars 44 comprise hollow rectangular members which extend completely across the construction between longitudinally extending stationary supports 164. The rollers 24 are journaled in the stationary supports 164, and sprockets 166 are carried by the roller shafts for rotation of the rollers by means of chain drive 168. Suitable vertical members (not shown) extend upwardly from the longitudinal supports 164 for carrying frame members 170 which in turn support the plates 66. It will be apparent that the longitudinal members 164 and 170 of the supporting frame are spaced apart by a distance greater than the width of a frame so that the frame is freely movable between them. Similarly, the transverse supports 162 are located beneath the level of the conveyor so that these supports will not interfere with the frame movement.

In the operation of the construction, a frame 10 is moved by the rollers 24 until the frame engages the blade 142 for operating microswitch 140. Closing of the microswitch will initiate a sequence of operations resulting in automatic cutting of the frame corners. In this connection, initiation of the sequence to be described may be dependent upon closing of a microswitch 140 on both sides of the construction. With this arrangement, proper alignment of the frame will be assured prior to lifting of the frame by the bars 44.

Closing of the switch or switches 140 may operate to set into motion a series of operations at preselected intervals. Thus, suitable sequential switch means may be employed for controlling each operation following closing of the switches 140. The first operation comprises actuation of the piston 62 to lift the frame 10 into position adjacent the cutters 42. The next operation involves actuation of the pistons 72 to lock the frame in position relative to the cutters. As indicated, this operation may involve shifting movement of all of the plates 70 or one plate may be stationary with the diagonally opposite plate moving first and with the other two plates following after a suitable time delay. Once the frame is locked in position, the motors 106 are started, and the pistons are actuated to move the motors in an arcuate path whereby the bits 112 will achieve the corner cutting. At the completion of the cutting operation, the pistons 80 will move the cutters back to starting position, and the piston 62 will then be energized to lower the frame onto the rollers 24. The gates provided by the plates 142 will then open through operation of the pistons 40.

The'entrance gates 32 must be kept closed until the exit gates are opened to provide for discharge of a frame into the area 30. The pistons 34 are preferably actuated to close the gates in response to closing of the microswitches 140. At this time, the operator of the construction can place a new frame on the conveyor bed in the area 26 so that this frame will be ready for movement into the cutting area as soon as the gates 32 are opened. Opening of the gates 32 may take place during movement of a frame 10 out of the cutting area provided that the gates 38 are closed through operation of the piston 40 before the next frame reaches the end position. An electric eye may be employed to detect the movement of the end of the frame past the gate position. A similar arrangement may be employed for closing the gates 32 when the end of a frame has passed this position.

It will be understood that various changes and modifications may be made in the above described construction which provide the characteristics of this invention without departing from the spirit thereof particularly as defined in the following claims.

Iclaim:

l. A construction for cutting the corners of bed spring frames comprising a supporting bed for the frames, a cutter for each corner of one of said frames, means for moving the supporting bed and associated frame into position with each' comer being adjacent one of said corner cutters, means for automatically locating said comer cutters in a starting position after said frame has moved into position, means for operating said corner cutters for removing material from said frame and for moving each comer cutter along an arcuate path to provide curvilinear corner surfaces on the frame, and means for automatically removing said frame from the cutting position at the completion of the cutting operation to permit movement of the next frame into cutting position.

2. A construction in accordance with claim 1 wherein at least one of said corner cutters is stationary, and including means for shifting the other comer cutters into engagement with a frame after the frame is positioned adjacent said stationary comer cutter to thereby align the frame prior to commencement of the cutting operation.

3. A construction in accordance with claim 2 including means for first shifting the corner cutter diagonally opposite said stationary corner cutter to thereby lock said frame in position, and thereafter shifting the other comer cutters into engagement with the frame.

4. A construction in accordance with claim 1 wherein said corner cutters comprise routers, and wherein the means for locating said corner cutters operate to shift the corner cutters in a horizontal plane and wherein said supporting bed moves vertically from a first frame receiving position to a second position adjacent said cutters.

5. A construction in accordance with claim 4 wherein said routers each include a motor and a vertical extending cutter, plates for slideably supporting the movable routers, first drive 6. A construction in accordance with claim S-Wherein one of said routers is held stationary in its starting position during movement ofa frame into position for cutting, means for initially shifting the router diagonally opposite said stationary router into starting position after said frame is in position, and means for thereafter shifting the other routers into starting position, and including corner engaging means extending downwardly from the bottom surfaces of said plates whereby shifting movement of the routers to starting position operates to align and lock said frame for cutting of the corners.

7. A construction according to claim 1 wherein said supporting bed is horizontally disposed and is movable vertically upwardly to said position adjacent said corner'cutters, and including means for returning said supporting bed to its lower position at the completion of the cutting operation, and means for discharging the completed frame from the supporting bed and for introducing a new frame onto the bed.

8. A construction in accordance with claim 7 including driven conveyor rollers for moving said frames to a position beneath'said corner cutters prior to cutting and for discharging said frames from this position at the completion of cutting, and wherein said supporting bed comprises rail means normally positioned beneath the conveying surface of said rollers, and including means for reciprocating said rails for removing and replacing said frames on said conveyor bed.

9. A construction in accordance with claim 8 wherein said rollers are continuously driven, and including end gate means for stopping an uncut frame in said position beneath said cutters.

10. "A construction in accordance with claim 8 including switch means adjacent said end gate means, the uncut frame engaging said switch means to thereby initiate operation of the means for moving the supporting bed rails to lift the uncut frame to cutting position.

11. A construction in accordance with claim 10 including entrance gate means for preventing movement of the next uncut frame into position beneath said cutting means until completion of the cutting operation, and means for opening said end gate means and said entrance gate means in response to placement of a cut frame on said conveyor rollers. 

